Thursday in photos

British runner Mo Farah, the reigning Olympic 5,000 and 10,000 meter distance champion poses for photographers during a media opportunity backdropped by Tower Bridge in London, Thursday, April 18, 2013. The London Marathon will go ahead on Sunday despite security fears in the wake of the bomb blasts in the Boston race that killed at least three runners and injured many more. (AP Photo/Matt Dunham)Photo by Matt Dunham